Heater cut-out device for electric lamps.



No. 652,626. v Patented lune 26, |900. W. NERNST & H. N. POTTER.

HEATER GUT-UUTVDEVICE FDR ELECTRIC LAMPS.

(Applicltion led Sept. 12, 1899.)

UNITED STATES,

"PAQFENT OFFICE.

WAL'II-IER NERNsT ANUHENRY NOEL POTTER, 0F GTTINGEN, GERMANY, AssIGNoRsTo GEORGE wEsTINGHoUsE, oF Prr'rsBURG, PENNSYLVANIA.-

- srEcIFrcax'IoN forming put er Letten Patent No. 652,626, dated .Tunece, Ieoo.

Application iisd September 12. 899. Serial No. 730,213. (No model.)

To all whom it concern: .l

Be it known that we, WALTHER NERNsT, a subject of the Emperor ofGermany, and

V HENRY NOEL POTTER, a citizen of theUnited 5 States of America,residing at Gttingen, in

lthe Kingdomof Prussia, Germany, have invented certain new and .usefulImprovements inl Heater Cut-Out Devices for Electric Lamps, of which thefollowing isla specificalo tion.4 l

Our invention relates to that type of electric lamps in whichl thelight-giving element or glower is a non-conductor when cold, butbecomesa conductor when heated. lt5 Our invention relates .particularlyto current interrupting, or controlling devices used in connection withtheelectric heating devices ofautomatic lamps of the above-.men--.tioned type. In such automatic lamps it is tive relation to the glowerand instarting the glower to pass current through the heater by means ofa circuit in parallel to that in which the glower is located. tointerrupt the current in the said heater-I 'circuit after the glower hasbecomeI conducting and is in operation, and various means have beenproposed for'effecting this result'. I

In our experience we have found it desirable to make. use of a heatercut-out located in a chamber containing an inert gas and to operate thesame thermostatically by meatsy of heat generated in a steadyingresistance or ballast-conductor, also located in said cham- 35 ber.vWeiind, however, thatthe thermostatic devices hitherto employed arevery slow in returningto their circuit-'closing position by reason ofthe fact that the inclosed devices and the chamber in which they areiuclosed require considerable time to cool down to such a temperatureVas will permit the thermostat to restablish the heatercircuit. 'loavoid the leteets of the slow cooling and to render it possible torelight our lamp alrriost '45 immediately after having extinguished it,We make use of the meansLshown d1ag-ram- Imatically in the accompanyingdrawings, in

which- 1 Figures 1 and 2 are views, parti-ally sec- 5o tional and partlydiagrammatic, of two embodiments of ourinventi'ou..l

lpound section C and C.

usual to arrange Va heating device in opera- It is desirable Referringto Fig. 1, Gis the giower, and h the heater, both of which are supportedupon an insulating-base M. i

B is the steadying resistance or current-red 55 straining device and may-be of any suitable materiale-such, for example, as platinum or nickel.v i i' lV is the retu rn-ciro'uit terminal of c urrent' restrainingdevice B. *te

Near currentrestrainingdevice- B and warmed by it are located two stripsof com- The freeendof strip C extends around the free en dv oi strip C',so as to make contact at P with the remote 6 5 side of, the said end ofstrip C'. Each of strips C and C' is composed of two metals havingdifferent coeiiicients of expansion under the action of heat.Theyare-arranged with the side of greatest expansion coefcient 7o towarddevice B, and when warmed by the heat from said ballast they bend, awayfrom fit, strip C bending sooner and to a` greater extent'than strip C',thereby breaking contact between the end of the stripsiat P. 7 5 The twostrips C and C' when in contact are connected in series with: each otherand with the heater H. Strip C'is further con-' nected at W to aconductor Bfleading from a main 5 to one terminal of ballast B. The endof the heater H remote from that to which strip C' is connected and theend of the glower G remote from that to which device B is con- .nectedare provided with terminals which 'are connected together and to a'conductor 85- which in turn is connected tothe c urrentmain 6. Inaction our device operates 'as' follows;y Current iows `at lirs'tthrough conductor 3, strips C and C', heater H, andconductor 4, thusraising the temperature of the heater, y which imparts its heattotheadjacent glower G. `When the glower has become sufficlently' Iheated, it becomes conducting and current i ows through conductor 3,device B, the 95 glower, and conductor 4. The current trav- Y g ersingthe'last-named path heats up the rel strainingdevice B, which in turnheats strips C'and C', causing them to bend-,and thus break the contactat P, whereby. the further passage of current to the'heater H 1s.prevented. When now theope'ra'tion ofthe "loo lamp is interrupted-as,for instance, by means of a switch 7 in conductor ll-current ceases tomaintain the restraining device B at an elevated temperature and stripsC and C' cool off. Strip C, being located nearer to device B, is hotterand therefore cools more rapidly than strip C. llt follows that con;tact between strips C and C is'established at P'before the strips becomeentirely cold. The

lamp may be again set in operation at any vtime after contact isrestablished at P, and,

ther dnd thet the spark which occurs whenv the heater-circuit is brokenis not of the same size in hydrogen as in air, it being markedly smallerin the hydrogen atmosphere, which may be in part eccounted for by thesuperior heat conductivity ci? hydrogen. We do not, however, in generaluse en atmosphere of hydrogen under' i'nll atmospheric pressure in thechamber K, es an accidental .rupture oi the Walls. of the cheminer mightadmit air to form an explosive gas mixture within, We have iound as theresult of experiments that it the pressure of hydrogen Within chamber Kbe only about on e-dfteenth of atmospheric pressure the admission oi nirwill not canse an explosion, the hydrogen their being too dilute to burnenplosively. There, is, hor-v ever, no sharpiydeiined pressnre 'et whichexplosion begins, nor do we eiivsys consider it necessery to avoid thepossibility of explou sion, es frequently the chamber K mey'he solocated that an explosion can do no considerabie damage.v

We herve mede a. great vsriety'oi errange ments of the partsconstituting this device in order to adaptit to various conditions oi?prec tical service, end we do not, therefore, condue ourselves to enyspecial errengement. itis sutdcient for our purpose it the struc= tureand arrengement ci apparatus he such neto insure s quickly-reestablishedcontact 'by means whichjdepend in general upon the use of e temperetnregradient insteed ot .merely en elevation oi? temperatnreu Theinterruption of an electric cnrrent in en etmosphere of hydrogen es.distinguished from other inert gases, solch as nitrogen, sise hes ewider applicetion than we have specifi icelly illustrated.,

'We claim es onr inventionj Y l, in on electric lamp having gior/erwhich requires the npplicetion ci host to render it conductive, thecomhinetion with such gloiver, of e heater proximity thereto, e

current-restraining device in series the glorrei, and en interruptor fortheynestermciiau straining ldevicethan the other.

cuit comprising two thermostatic arms movable in the same directionunder the induence of the heat developed in the current-redevice, one ofsaid arms being in closer proximity to said4 current-restraining 2. Inan electric lamp having a glower which requires the application of heatto render it condnctive,the combination with such' glower, of a heaterin proximity thereto, a current-restraining device in series with theglower, and a making and breaking device for the beater-circuitcomprising two thermostatic arms located in proximity to thecurrent-restraining device but at different distances therefrom',whereby they move in the` same direction but in' unlike degree under theinfinence of heat. i

' 3. In an electriclamphavingaglower'which requires the application ofheat to render it conductive, the combination with such glower, of nheater in proximity thereto, a current-restraining device in series withthe glower, a making and breaking device for the hcaterycircnitcomprising two thermostaticarms, and a chamber for the restrainingdevice and the thermostatic arms containing hydrogen., f

4i, A circuit-breaking device comprising two thermostatic arms, meansfor applying heat thereto and an inclosing chamber therey for containinghydrogen.

5, A circuit-breaking device comprising two thermostatic arms, heatingmeans for said orme located nearer to one than the other, sindaninciosing chamber therefor containing hydrogen.

6. in an eiectriclamp of the type described, the combination withtheglower end n oure vrent-restrroining device therefor, ot e hector inproximity to the glovver, :and making end breaking means for theheeter-circnit comprising two thermostatic arms ,one of which l Vhes itshody portion and'its contact end on opposite sides ot the other arm,said corren trestraining device being located adjecent to said bodyportion.

i?. in en electriclemp of the 'type described,

the combination with a viewer end e cnrrentn restraining devicetherefor, ci hector in proximity to the giower and melting and breakingmeans for the hentercircuit comprising e short and e. long thermostaticarm, the latter of which extends around the former to maire contact withits remote side,thecur rent-restraining device being located inproximity to said long erm;

lin witness whereof we hnve heren nto signed I onr names, this 10th deyof August, 1899, in the presence of two subscribingwitnesses.

tranci-infn Nenner,

HENRY Nom] PUTTER.

Witnesses: v

Fermi-enten von' Venous. `Wcenni/ren Heuer.

reg

